In the steel pipe weld annealing, there are two types of steel pipe longitudinal welds and annealing on the weld welds, and the two methods have been described in detail.
1. A longitudinal direct weld annealing steel pipe longitudinal welds in the longitudinal direction of steel pipe is to refine the grains. With induction heating, only the weld tube of the wall thickness of 8 to 15 mm, the weld width is about 20 mm.
2. Docking steel pipe weld annealing annealing, generally employ a circular sensor, from induction heating electric efficiency, a higher frequency, that is, steel tube wall thickness / d800 ° C3.5.
3. Steel pipe weld annealing hardness and microstructure inspection of the microstructure of the normal fire area must be similar to the metal metal metal, the grains of the thermal influence zone are thick, indicating that the normal fire temperature is too high; the heat affected zone The hardness is higher than the base material, indicating that the normal fire temperature is too low; if a small amount of crude grain mixed in the microstructure is mixed in many small crystal grains, indicating that the normal temperature temperature is slightly lower.